Furnace rolls



Dec. 24, 1963 M. N. oRNn'z r-:TAL

FURNACE ROLLS 2 Sheets-Sheet 1 Original Filed May 15, 1961 INVENTORS Martin N.Ornitz 8 Harry. Rees James me ATTORNEYS Dec. 24, 1963 M. N. oRNlTZ ETAL 3,115,335l

FURNACE ROLLS 'original Filed May 15, 1961 2 Sheets-Sheet 2 INVENTORS Martn N. Ornifz 6 l Harry. Rees James fheir ATTORNEYSv United States Patent() 3,115,335 FURNAJCE RLLS Martin N. Urnitz, Wiilrinsburg, Pa., and Harry Rees fairies, deceased, late of Pittsburgh, Pa., by Esteiia T. James, executrix, Pittsburgh, Pa., assignors to Blaw- Knox Company, Pittsburgh, Ila., a corporation of Deiaware Continuation of application Ser. No. 109,964, May 15, 1961. This appiieation .luly 26, 1963, Ser. No. 298,53S 12 Claims. (Ci. 26S- 6) This invention relates to furnace rolls and particularly to water cooled furnace rolls for use in conveying sheets, plates and the like in high temperature vessels. This application is a continuation of the co-pending application of Martin N. Ornitz and Harry Rees I ames, filed May 15, 1961, bearing Serial No. 109,964.

The use of conveyor rolls for high temperature furnaces goes back many years. When the use of such rolls was rst conceived, they were used to carry packs which were about thirty inches wide. These furnaces were operated at lower temperatures than modern furnaces, were of much narrower widths and carried far smaller loads. Where these earlier furnaces were of about forty inch maximum width, modern furnaces are as Wide as two hundred twenty (220) inches; the loads were small packs or laminates of sheets whereas modern conveyors are expected to carry heavy plates up to about four inches thick and the temperatures have gone from 1600 F. to as high as 2400 F. in the same period. This change in furnace design, loading and temperature brought many changes in roll design. The first rolls used were hollow rolls through which water flowed. As the temperatures, widths and loads increased, these early water cooled rolls were discarded in favor of dry hollow rolls of high temperature alloys. Continued increase in widths and loads made it necessary to go to heavier and heavier rolls until they became uneconomical. At this point, the industry attempted to go back to the practice of flowing Water through hollow rolls. However, the higher temperatures lead to excessive heating of the water, vapor locks and vaporization of the water. This vaporization of the water leads to serious accidents from time to time with steam blown from the roll ends at high pressure, as well as cracked rolls. The result was that the conventional water cooled roll has not proved satisfactory for modern furnace structures.

The present invention provides a roll structure which overcomes these problems and provides the necessary support, light weight and cooling effect. In a preferred embodiment there is provided a hollow central cylindrical shaft, hollow roll necks at each end of said shaft providing inlet and outlet ports, an aixal cylindrical tube extending lengthwise within said hollow shaft from a point adjacent one end to a point adjacent the other and equally spaced from the internal walls of the shaft. A bulkhead in said tube closes said tube against axial flow therethrough. The end adjacent the inlet port is preferably ciosed with the bulkhead to provide a narrow annular passageway between the thimble and the interior wall of the shaft. A constricting ring is preferably adjacent the outlet end of the annular passage to retard the flow of water out of the passage. An outer annular load bearing sleeve preferably surrounds the cylindrical shaft spaced therefrom and separated therefrom by insulating material.

In the foregoing general description of this invention certain objects, purposes and advantages have been set out. Other objects, purposes and advantages of this invention will be apparent from the following description and from a consideration of the accompanying drawings in which,

3,115,335 Patented Dec. 24, 1963 ICC FIGURE l is a side elevaiton of a central shaft according to our invention;

FIGURE 2 is a side elevation partly in section according to FIGURE 1;

FIGURE 3 is a section on the line III- III of FIG- URE 1;

FIGURE 4 is a section on the line IV--IV of FIG- URE 1;

FIGURE 5 is a side elevation of the axial tube;

FIGURE 6 is an elevational view of the constricting ring;

FIGURE 7 is a side elevational view of a second embodiment of a roll according to our invention;

FIGURE 8 is a section on the line VIII-VIII of FIG URE 7; and s FIGURE 9 is an end elevation of the load carrying disc of FIGURES 7-8.

Referring to the drawings there is illustrated a water cooled shaft 10 made up of a hollow cylindrical shaft body 11 provided with hollow roll necks 12 and 13 at each end having conical inlet 14 and outlet 15 ports. Each port 142- and 15 is connected to a hollow axial passage 16 through the neck and a water line fitting 17 at each end. Each neck is also provided with a keyway 17a for connection to a drive member, not shown. A hollow axial tube 18 extends axially of the interior of the shaft body 11. The tube 18 is closed at the end 19 adjacent the inlet port 12 and open at the opposite end. Spacers 20 on the periphery of the tube space it equidistant from the interior of the walls of the shaft 11. A spacer or constricter ring 21 is threaded onto a threaded neck 22 on the open end of tube 18. The spacer ring 21 is provided with spaced ports 23 whose total area is less than the area of the inlet passage 16 so as to restrict the iiow of coolant along the surface of tube 18 beneath the surface of shaft 11.

The external periphery of shaft 11 is provided with spacer lugs 24 over which an outer high temperature alloy sheath 25 is placed. The spacer lugs 24 may be coated with a refractory oxide or other heat retarding coating such as stabilized zirconia, alumina or the like to retard the cooling effect of the lugs 24 on the sheath 25. In short the coating acts as a thermal barrier and prevents cold spots on the sheath surface. The area between the alloy sheath 25 and the outer surface of shaft 11 is filled with insulation 26 whose nature and density may be varied to control the amount of cooling effect to be achieved on the sheath 25.

In operation, coolant, such as water, is introduced under pressure through inlet passage 16 into inlet port 14. The water entering the interior of shaft body 11 passes over end 19 and around tube 18 through the ports 23 of the constrictor ring 21. Ring 21 retards the iiow of coolant and maintains the area between the tube 18 and shaft body 11 full of coolant under pressure. The coolant leaving ports 23 fills tube 18 and the excess passes out through outlet port 15 and passage 16.

Normally a suiiicient amount of insulation 26 is provided between the cylindrical shaft surface 11 and the high temperature sheath 25 to prevent any heat transfer between the shaft body and the outer sheath. However, where it is desired to operate the roll in extremely high temperatures the insulation may be controlled so as to provide a controlled degree of heat transfer. For example, rolls using BiaW-Knox Companys Z2-H alloy as the outer sheath 25 will operate at temperatures up to 2200 F. without any heat transfer being desired. At temperatures of 2400 F. or thereabout, it is desirable to control the effect of insulation so as to provide controlled conduction from sheath 25 to shaft body 11 so as to maintain a temperature of about 2200" F. in the D sheath 25. lt is desirable to operate the roll with the sheath 25 at the highest possible temperature in order to avoid an undue heat loss from the furnace.

In the embodiment illustrated in FIGURES 7-9 there is illustrated a high temperature conveyor roll having a shaft body lla, an inner tube fida, roll necks 12a and 13a all corresponding precisely to those of FIGURES 1 through 6. The outer sheath 25a is formed of high ternperature alloy and is spaced from the outer surface lla of the shaft body precisely as in FIGURES l through 6. Sheath 25a is provided, however, with splines 3) extending along its surface. Alloy bearing discs 3l (FlG- URE 9) are slid onto the sheath 25 at spaced apart positions with keyways 32 engaging the splines 30. These discs 3l are used to carry the load of material through the furnace and provide access to all parts of the load in the furnace, thus insuring more rapid and uniform heating of the work.

Certain preferred embodiments of this invention have been set out hereinabove, however, it will be understood that this invention may be otherwise embodied within the scope of the following claims.

We claim:

l. A furnace conveyor roll adapted to carry a coolant comprising a hollow-cylindrical body having inlet and outlet ports in opposite ends thereof, an axially extending tube imperforate intermediate the ends thereof in said body spaced from the internal walls thereof, fori ing an annular passage therebetween through which coolant is passed, means in said tube closing said tube against passage of duid therethrough, constricting means between the tube and the internal Wall of the said body restricting the area of the passage at the constricting means to no greater than the inlet area of the inlet port, and a load bearing surface on said body.

2. A furnace conveyor roll as claimed in claim l wherein spacer means extend radially from the body and carry the load bearing surface spaced from said body and separated therefrom by an insulant.

3. A furnace conveyor roll adapted to carry a coolant comprising a hollow-cylindrical body having inlet and outlet ports in opposite ends thereof, an axially extending tube imperforate intermediate the ends thereof in said body spaced from the internal walls thereof, forming an annular passage therebetween through which coolant is passed, said tube being closed at the end adjacent the inlet port against passage of fluid therethrough and open at the opposite end, constricting means between the tube and the internal wall of the said body at the end adjacent the outlet means restricting the area of the passage at the constricting means to no greater than the inlet area of the inlet port, and a load bearing surface on said body.

4. A furnace conveyor roll as claimed in claim 3 wherein the hollow-cylindrical body is provided with radially extending spacer means and the load bearing surface is a sleeve of high temperature alloy on said spacer means.

5. A furnace conveyor roll as claimed in claim 4 wherein the space between the body and the sleeve is filled with insulating material.

6. A furnace conveyor roll adapted to carry a coolant comprising a hollow-cylindrical body having inlet and outlet ports in opposite ends thereof, an axially extending tube imperforate intermediate the ends thereof in said body, radial spacer means on the tube spacing it equidistant from the internal walls thereof and forming an annular passage therebetween through which coolant is passed, Means in said tube closing said tube again passage of fluid theretirough, constricting means betW-en the tube and the internal wall of the said body ad'acent the outlet port restricting the area of the passage at the constricting means to no greater than the inlet area of the inlet port, radial spacer means on the periphery of the cylindrical body and a load bearing sleeve removably on said spacer means.

7. A furnace conveyor roll adapted to carry a coolant, comprising a hollow-cylindrical body having inlet and outlet ports in opposite ends thereof, an axially extending tube imperforate intermediate the ends thereof in said body spaced from the internal walls thereof and forming an annular passage therebetween through which coolant is passed, rneans in said tube closing said tube against passage of fluid therethrough, constricting means between the tube and the internal wall of the said body adjacent the outlet port restricting the area of the passe-.ge at the constricting means to an area no greater than the inlet area of the inlet port, radial spacer means on the periphery of the hollow cylindrical body, a sleeve on said spacer means, axially extending ribs on said sleeve annular load bearing rings slidably engaging said ribs spaced axially along said sleeve.

8. A furnace roll as claimed in claim 7 wherein insulant surrounds the spacer means on the body between the body and the sleeve.

9. A furnace roll as claimed in claim 4 wherein the spacer means is coated with a thermal barrier.

l0. A furnace roll as claimed in claim 4 wherein the spacer means is coated with a refractory metal oxide.

ll. A furnace conveyor roll adapted to carry a coolant compr` .ng a hollow-cylindrical body having inlet and outlet ports in opposite ends thereof, an axially extending tube imperforate intermediate the ends thereof in said body spaced from the internal walls t iereof, forming an annular passage therebetween through which coolant is passed, means in said tube closing said tube against passage of fluid therethrough, connecting means between said tube and internal wall of the body holding said tube therein, passageways connecting the inlet and outlet ports to the annular' passage between the body and tube, and a load bearing surface on said body.

l2. A furnace conveyor roll for conveying sheets, plates and the like through high vtemperature vessels comprising a hollow cylindrical shaft body terminating in roll necks at each end, a tube within said body extending axially between ends adjacent to said roll necks, said tube being laterally spaced from the internal cylindrical Wall of said body forming an annular coolant passage between said body and said tube and being imperforate intermediate the ends of said annular coolant passage, an inlet connection through one of said roll necks for introducing cooling water into said annular passage at one end thereof, an outlet connection through one of said roll necks for withdrawing cooling water at the opposite end of said annular passage and means closin said tube against direct passage of cooling water therethrough from said inlet connection to said outlet connection.

References @lated in the file of tris patent UNITED STATES PATENTS 1,468,837 Schreck Sept. 25, 1923' 1,754,826 Hitchcock Apr. l5, 1930 1,923,772 Carpenter Aug. 22, 1933 2,025,547 Ornitz Dec. 24, 1935 2,984,473 Ornitz et al May 16, 196i 

11. A FURNACE CONVEYOR ROLL ADAPTED TO CARRY A COOLANT COMPRISING A HOLLOW-CYLINDRICAL BODY HAVING INLET AND OUTLET PORTS IN OPPOSITE ENDS THEREOF, AN AXIALLY EXTENDING TUBE IMPERFORATE INTERMEDIATE THE ENDS THEREOF IN SAID BODY SPACED FROM THE INTERNAL WALLS THEREOF, FORMING AN ANNULAR PASSAGE THEREBETWEEN THROUGH WHICH COOLANT IS PASSED, MEANS IN SAID TUBE CLOSING SAID TUBE AGAINST PASSAGE OF FLUID THERETHROUGH, CONNECTING MEANS BETWEEN SAID TUBE AND INTERNAL WALL OF THE BODY HOLDING SAID TUBE THEREIN, PASSAGEWAYS CONNECTING THE INLET AND OUTLET PORTS TO THE ANNULAR PASSAGE BETWEEN THE BODY AND TUBE, AND A LOAD BEARING SURFACE ON SAID BODY. 